I recently purchased a 68 Cutlass with the original 2 speed automatic transmission in it. It was apparently rebuilt about 16000 miles ago.... which was also about 20 years ago.

It runs pretty strong, but every once in a while it has trouble shifting from 1st to 2nd. I checked the level and color of the fluid. The color was a very clear pink and the level looked low. I added about a half a pint of fluid and the next time I drove it the results were great. Unfortunately today it seemed to occasion sputter and have inconsistent RPMs. Any suggests on what to check aside from the fluid again?

 

Check the vacuum modulator and the hose going to it. This can delay upshifts to wide-open-throttle and high RPMs.

 

Excuse my ignorance, where is the vacuum modulator and what do I really need to check for? This is my first time dealing with the transmission .

 

Ok, so it seems that is is getting a little worse. Still having the issue of having trouble shifting sometimes. Took a co-worker for a spin to show him (he has had 12+ Cutlass in his day) and of course it ran great. On my way back to my house it, it jumped a little more and sometimes sounded like it was going to die after being in idle for a while (possible other issue?). Then in my driveway I had it in park (still running to move trashcans in my garage) and it was a little more difficult to shift into drive. So what would you do to troubleshoot this?

1) Check vacuum modulator - Where is it?
2) Flush transmission fluid and change filter - Can has been driven 2000 miles in the past 12 years. Is it difficult to change all this?
3) Rebuild Transmission
a) What is average cost of this?
b) Should I just buy a different transmission or keep it original

Thanks